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Thursday, July 15, 2010

More Asthma and Risk of Asthma Drugs

UPDATE: 15 July, 2010 - Interferon is known to cause liver and kidney failure. St. John's wort is a natural interferon.

Interferon may help stop asthma

DALLAS, July 15 (UPI) -- U.S. researchers suggest the protein interferon may help block immune cells known to cause asthma.

Researchers at the University of Texas Southwestern Medical Center in Dallas say interferon -- an immune-system protein used to treat multiple sclerosis, hepatitis C and a number of cancers -- may help asthma patients breathe easier.

The study, published in the Journal of Immunology, finds interferon blocks the development of immune T lymphocytes cells known as T helper 2 cells, which help protect against infection but in some individuals also promote allergic responses to substances such as animal dander and pollens. Once these cells become reactive they promote all of the inflammatory processes common to an allergic disease like asthma.

"This finding is incredibly important, because humans are being treated with interferon for a variety of diseases, yet no one has tried treating asthma patients with interferon," Dr. J. David Farrar, the study senior author, said in a statement. "The current therapies for asthma are inhalers and steroids, both of which offer only temporary relief."

Farrar and colleagues determined in isolated human cells that interferon blocks the development of the T helper 2 cells by interfering with a transcription factor.

A landmark survey conducted on street corners in Dorchester shows that African-Americans born in this country are nearly three times more likely to have asthma than their black neighbors born abroad, a finding that could yield important clues about a national epidemic.

The study was conceived in 2005 by frustrated residents of Dorchester who wanted to understand why asthma is rampant in their neighborhood. The results appear in the November edition of the Journal of Asthma.

It is believed to be the first study to show varying asthma rates among African-Americans based on place of birth - although scientists can't say for sure why Dorchester blacks born outside the United States suffer less from asthma.

"It has a through-the-looking-glass feel to it," said Doug Brugge, the researcher at Tufts University's medical school who presided over the study. "We're used to thinking that people coming from developing countries have worse health."

Theories for the disparity range from more sunlight exposure for foreign-born African-Americans during childhood, to less time spent cooped up inside, where mold, cockroach droppings, and other triggers dwell.

One of the most provocative - and even paradoxical - suggestions involves something called the hygiene hypothesis: Because natives of other nations, especially those in the developing world, may encounter more infections growing up, their immune systems often ignore threats such as dust mites and mold. When the immune system does not regularly confront life-threatening diseases, its ammunition instead is directed at lesser enemies, provoking allergic reactions that can spawn asthma.

"There may be a price to be paid for growing up in a more sterile, hygienic environment with fewer infections as a child," such as the United States, said Dr. George O'Connor, director of the Adult Asthma Program at Boston Medical Center. "And the price to be paid is that your immune system may develop more along the lines of promoting allergic responses."

The Dorchester findings did not come as a total surprise: Earlier research had shown that foreign-born Asians and Hispanics appear less prone to the disease.

The discovery is another piece in the emerging jigsaw puzzle of asthma, which has roughly doubled in prevalence nationally during the past three decades.

Evidence of the epidemic can be heard all across Dorchester, as the sounds of suffering ricochet through homes: coughing jags, raspy wheezing, chest-clenching gasps for air - and time spent in clinics rather than at school and work.

Everywhere Mary White turns, the Boston native finds someone whose life has been defined by the disease, she says, starting with her own. She has asthma and so do her three sons, and her mother. So did her deceased father.

"When you ask a person, 'Do you have asthma? Do you know what asthma is?' and then you look in their eyes, you see something, because everyone has someone in their family with asthma," said White, a member of the Boston Urban Asthma Coalition, an advocacy group. "But we wanted to get it on paper."

So they approached Brugge and asked him to study asthma in Dorchester, as he had done in Chinatown. He agreed - and then enlisted the people of Dorchester to help collect the data.

They stationed themselves at T stations, grocery stores, and laundromats.

"You're sitting there waiting for your clothes to dry, and you're always talking to the person next to you - so why not talk to me?" said Neal-Dra Osgood, coordinator of the asthma coalition's Strengthening Voices project, which works to provide support for families of asthma sufferers.

Using a carefully constructed survey, nearly 20 parents and Harvard medical students fanned out across Dorchester in 2005 and 2006, with findings on 290 adults and 157 children included in the analysis.

"The idea is that community members know something about the disease that outsiders don't, both how it affects their bodies and their families, but also, more importantly, about the community context," said Jason Corburn of the University of California at Berkeley, who studies the intersection between community involvement and urban environmental health, an ethos neatly summarized in the title of his book "Street Science."

The study found that 30 percent of African-American adults who were US natives had been diagnosed with asthma, compared with 11 percent of blacks born elsewhere. Researchers cautioned that the study is a snapshot of only one neighborhood.

Still, it reflects an emerging recognition that scientists should stop regarding racial and ethnic groups as monoliths. "We have to be really aware that using a broad brush, you're going to miss some really important differences," said Dr. Lauren Smith, medical director of the Massachusetts Department of Public Health.

Asthma has rampaged across New England in recent years; one study estimated that the number of people in the region diagnosed with the condition rose by 400,000 from 2001 to 2004. The disease is more common here than anywhere else in the country, with one in seven adults and children affected.

Studies have shown that children who spend pivotal growing-up years in farming areas are strikingly less likely to develop asthma. Researchers theorize - and biological tests suggest - that exposure to germs during childhood reduces reaction to allergens. But it remains unclear what to do with that finding.

"Do you definitely want people here to start dealing with all the issues other countries have outside the United States in order to get rid of asthma and allergy?" said Dr. Wanda Phipatanakul, an allergist at Children's Hospital Boston.

Mary White dealt with her family's asthma by moving out of the mold-ridden, vermin-attracting apartment in the South End where they lived. Now, home is a two-family in Dorchester. Shoes never touch the living room floor. Dust is quickly banished. And the floors glisten with shiny wood instead of wall-to-wall carpeting. All help reduce the asthma symptoms.

She always knew in her heart, White said, that asthma placed an especially heavy burden on her neighborhood. But with the study, "someone's going to listen to you now," she said. "It's proof. And proof is important."

FDA advisers weigh risks of asthma drugsBy RICARDO ALONSO-ZALDIVAR, Associated Press Writer
Wed Dec 10, 2008
WASHINGTON – In recent years, millions of asthma patients have started using long-acting drugs to help them breathe more normally, allowing for nights of uninterrupted sleep or workouts at the gym.

Now the Food and Drug Administration is investigating whether the medications, in rare cases, can increase the risk of serious asthma complications, the kinds that send patients to the emergency room gasping for air. At a two-day meeting that begins Wednesday, independent medical advisers will hear the scientific evidence and make recommendations on whether the drugs should continue to be used to treat asthma.

At issue are four inhaler medications: Advair, Foradil, Serevent and Symbicort. Within the FDA, opinions appear to be divided. The safety office is recommending that Foradil and Serevent no longer be used for asthma, and that none of the drugs be used by children 17 and under. But the head of the FDA office that oversees respiratory medications has written that banning the drugs would be "an extreme approach," and could backfire by leading to more cases of uncontrolled asthma.

The companies that make the medications say they are safe, and that at least some of the medical evidence that has raised questions from the FDA is of poor quality. Doctors who treat asthma patients are worried that the drugs could be banned.

"We would lose a medicine that patients find helpful," said Dr. Paul Greenberger of Northwestern University in Chicago, president-elect of the American Academy of Allergy, Asthma & Immunology. "We would be going backward, and the consequences of that would be more untoward effects of asthma. That's a major deal, because asthma hospitalizations continue to be too high."

The four drugs contain a kind of long-acting medication known as a LABA (for "long-acting beta 2-adrenergic agonist"). The drug relaxes tight muscles around narrowed airways. Medical guidelines for treating moderate to severe asthma recommend use of a LABA together with a steroid, which treats inflammation deep inside the airways.

Foradil and Serevent are LABA-only products. Advair and Symbicort combine a LABA and a steroid in one inhaler that patients use every 12 hours. Asthma patients must also carry a "rescue" inhaler to deal with the sudden onset of symptoms.

Some experts believe that using a LABA drug alone can mask developing symptoms, and unexpectedly get patients in trouble. That's why medical guidelines call for LABA medications to be used along with a steroid.

In preparation for the meeting, the FDA analyzed findings from 110 clinical trials involving nearly 61,000 patients, comparing patients who took a medication containing a LABA with those who used a steroid alone to control their asthma. Experts looked for deaths, hospitalizations and cases in which a patient had to have a breathing tube inserted.

The analysis found 20 deaths from asthma complications, of which 16 were in patients taking a LABA-only drug, Serevent.

Advair, a widely used medication made by GlaxoSmithKline, did not appear to have a higher rate of serious complications when compared with treatment on steroids only. Foradil, Serevent and Symbicort all had higher rates of problems, but the increase was statistically significant only in the case of Serevent.

3 comments:

Anonymous
said...

I know a few black immigrants who developed asthma after emigrating to Canada, and what is starling is that they developed the asthma as adults, these are non-smokers too. A larger percentage develop allergies after living here for a while.

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